Business owners across Australia know the importance of lodging their Business Activity Statement (BAS) on time. The BAS helps report and pay GST, PAYG instalments, PAYG withholding, and other taxes to the Australian Taxation Office (ATO).

But let’s face it—mistakes happen. Whether it’s misreporting GST, forgetting to include an invoice, or entering wrong numbers, BAS errors are very common. The good news is that the ATO provides clear ways to fix them. In this guide, we’ll explain how to correct an error in your BAS lodgment, avoid penalties, and stay compliant.

Why BAS Errors Happens

Even with the best intentions, BAS errors can occur due to:

• Data entry mistakes – typing errors while recording amounts.
• GST misreporting – claiming GST where it’s not eligible or missing credits.
• Forgotten invoices or receipts – leaving out important transactions.
• Incorrect PAYG withholding – reporting wrong employee tax figures.
• Manual bookkeeping – relying on paper records instead of software.

Understanding why mistakes happen helps business owners take steps to prevent them in the future.

Types of BAS Errors

Not all errors are treated equally by the ATO. They usually fall into two categories:

1. Minor errors – Small miscalculations or minor reporting mistakes. These can usually be corrected in your next BAS lodgment.
2. Significant errors – Major issues like overstated GST credits, incorrect PAYG withholding, or large figures entered in the wrong sections. These often require a revision of the already lodged BAS.

Knowing which type of mistake you’ve made is the first step to correcting it properly.

How to Identify Errors in Your BAS

Catching mistakes early reduces stress and avoids penalties. Here’s how you can spot them:

• Reconcile your accounts regularly – Match your business bank account, invoices, and expenses with your BAS records.
• Use bookkeeping software – Tools like Xero, MYOB, or Reckon automatically calculate GST and reduce errors.
• Review ATO notices – Sometimes, the ATO may send a notice highlighting differences between their records and yours.

How to Correct a BAS Error

The correction process depends on whether your BAS has been lodged already and how serious the mistake is.

1. If the BAS Has Not Been Lodged Yet

This is the easiest case. Simply log back into the ATO Business Portal or your accounting software, make the changes, and then submit.

2. If the BAS Is Lodged and the Error Is Small

For minor mistakes, you can usually fix them in your next BAS. For example, if you forgot to claim a $50 GST credit, simply include it in the following period.

3. If the BAS Is Lodged and the Error Is Significant

For larger mistakes, you must revise your BAS. You can do this through:

• The ATO Online Services for Business portal
• Your registered BAS or tax agent

The ATO allows you to make corrections within four years for most BAS errors.

4. If You Are Unsure

When in doubt, it’s best to seek help from a BAS accountant or tax professional. They understand compliance rules and can ensure your correction is done properly.

Possible Penalties for BAS Errors

The ATO understands that errors happen, but penalties may apply if:

• You deliberately misreport information.
• You consistently make careless errors.
• You fail to correct mistakes promptly.

Penalties may include:

• Interest charges on unpaid amounts.
• Administrative fines depend on the size of the error.

Correcting mistakes early and honestly usually reduces or removes penalties.

Tips to Avoid Future BAS Mistakes

Prevention is always better than correction. Here are some practical ways to reduce BAS errors:

• Maintain accurate records – Keep receipts, invoices, and payroll records updated.
• Reconcile monthly – Don’t wait until the quarter ends. Regular reconciliation makes BAS preparation easier.
• Use cloud accounting software – Automating GST calculations lowers the risk of human error.
• Work with a BAS agent – A registered agent can review your BAS, lodge it on time, and correct errors quickly.

Final Thoughts

Making a mistake on your BAS isn’t the end of the world. Errors are common, but the ATO provides clear solutions to fix them. Whether it’s adjusting your next BAS, lodging a revision, or consulting a Perth accounting service, correcting mistakes early keeps your business compliant and stress-free.

If you’re unsure about how to fix an error in your BAS lodgment, don’t panic. Review your records, identify the mistake, and act quickly. And remember, getting professional help from a registered BAS agent can save you both time and money.

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